syzbot


KCSAN: data-race in dequeue_signal / ptrace_check_attach (8)

Status: moderation: reported on 2024/04/28 05:34
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+678dba881548c41d578a@syzkaller.appspotmail.com
First crash: 51d, last: 30d
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (6) kernel 1 250d 250d 0/27 auto-obsoleted due to no activity on 2023/11/16 03:30
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (7) kernel 13 86d 189d 0/27 auto-obsoleted due to no activity on 2024/04/27 21:52
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (5) kernel 3 289d 351d 0/27 auto-obsoleted due to no activity on 2023/10/08 11:58
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (3) kernel 3 474d 499d 0/27 auto-obsoleted due to no activity on 2023/04/16 11:35
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (2) kernel 1 544d 544d 0/27 auto-obsoleted due to no activity on 2023/02/02 07:54
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach kernel 1 647d 647d 0/27 auto-obsoleted due to no activity on 2022/10/15 10:03
upstream KCSAN: data-race in dequeue_signal / ptrace_check_attach (4) kernel 2 413d 422d 0/27 auto-obsoleted due to no activity on 2023/06/06 04:16

Sample crash report:
==================================================================
BUG: KCSAN: data-race in dequeue_signal / ptrace_check_attach

read-write to 0xffff888101eb36a8 of 8 bytes by task 21564 on cpu 0:
 dequeue_signal+0x3de/0x430 kernel/signal.c:685
 get_signal+0x37d/0x1080 kernel/signal.c:2790
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101eb36a8 of 8 bytes by task 25212 on cpu 1:
 ptrace_freeze_traced kernel/ptrace.c:189 [inline]
 ptrace_check_attach+0x7f/0x290 kernel/ptrace.c:256
 __do_sys_ptrace kernel/ptrace.c:1280 [inline]
 __se_sys_ptrace+0xd4/0x2b0 kernel/ptrace.c:1258
 __x64_sys_ptrace+0x55/0x70 kernel/ptrace.c:1258
 x64_sys_call+0x296f/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:102
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0x0000000008010000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25212 Comm: syz-executor.2 Not tainted 6.9.0-syzkaller-08544-g4b377b4868ef #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/18 14:37 upstream 4b377b4868ef c0f1611a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dequeue_signal / ptrace_check_attach
2024/04/28 05:33 upstream 5d12ed4bea43 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dequeue_signal / ptrace_check_attach
* Struck through repros no longer work on HEAD.